An analysis of the catalysis of Fe, Ni or Co on the wear of diamonds

The desorption probability for hydrogen chemisorbed on diamond surface is discussed. A model including the equilibrium partial pressure of H2O resulting from oxidation of methane by metal oxides allows the wear rate of diamond to be computed based on the assumption that the wear mechanism involves diffusion. The calculated partial pressure of H2O suggests that diamond–graphite phase transformation occurs at the surface layer of diamond tools cutting Cu, Ni, Co or Fe. The calculated wear amount of diamond agrees well with the experimental data, when the temperatures of the cutting interfaces are assumed 560 °C for the cutting of Fe and 600 °C for Ni.